1. Field of the Invention
The present invention relates to air pumps. More specifically, the present invention relates to methods and apparatus for an internal air pump for use with inflatables, i.e., inflatable devices, such as an air mattress, and which includes a thin-walled, highly elastic, lightweight, robust, durable, flexible plastic construction which is self-adjusting and highly reliable against failure.
2. Description of the Prior Art
The prior art is directed to methods and apparatus for internal air pumps for use with inflatable devices such as, for example, air mattresses. The use of inflatable devices fabricated from modern lightweight plastics has increased in recent years. Inflatable devices are now typically found in camping equipment, residential and beach air inflatable furniture, swimming pool lounging equipment, watercraft and the like. Therefore, advances in means for inflating the myriad of inflatable devices has occurred.
Inflatable devices and objects known in the past were often comprised of heavy gauge plastic, rubberized and other synthetic materials which were not convenient to inflate and transport. Typically, an external air pump was required in order to inflate these devices prior to their use. These inflatable devices included an externally accessible air valve which was compatible with the external air pump used to inflate the device. Likewise, after use, it was necessary to exhaust the air pumped into the inflatable device prior to disassembly and storage thereof.
With the advent of lightweight, robust plastic materials now utilized to fabricate inflatable devices, modifications in the manner in which these devices were inflated have occurred. Generally, designs referred to as foam spring or foam activated air pumps, in block form, which are employed as the air pumping mechanism have been known. Each of these designs have certain characteristics in common which include (a) the foam spring or foam activated mechanism is positioned within a small air chamber or housing of the air pump which in turn is located within an outer larger air mattress chamber, and (b) each of these foam spring type pumps have an intake port and an exhaust port for the intake and exhaust of air.
In a first example, an air mattress is disclosed including a pump contained within an inflatable chamber. The pump is in fluid communication with the inflatable chamber via intake and exhaust ports. One way valves positioned on the intake and exhaust ports of the pump control the flow of air from the pump to the inflatable chamber of an air mattress. The pump contains a solid block of resilient, closed-cell foam pump material which functions as a piston head pushing air out of the exhaust duct and into the inflatable mattress. When foot pressure is released, the slightly compressed solid block of foam is released, the air intake valve opens to draw air into the inner housing and the exhaust valve closes.
In a second example, an air mattress is disclosed that incorporates within it a pump having a variable volume chamber formed by a flexible sheeting material. Located within the chamber is a large block of open-cell foam material which biases the chamber to its maximum volume. An air outlet incorporating a one way valve restricts air to move outwardly from within the chamber while an air inlet is maintained clear during a pumping operation and is selectively closed by the hand of the operator. On a compression cycle, the foot forces the large block of open-cell foam material down to force air out of the exhaust port to the inflatable device. On release of the foot, the foam block recovers and the valves operate to open the intake port and close the exhaust port.
In another example, a self-inflating air mattress is disclosed which includes an air chamber and a foam panel therein. The air chamber is defined by top and bottom sheet panels and a valve allowing air passage into and out of the air chamber. The foam panels includes apertures therethrough and the top and bottom sheet panels are mechanically coupled directly together via the apertures in the foam panel. As a result, the foam panel need not be mechanically coupled to the top and bottom sheet panels and improved air flow within the chamber results. In a further example, an air mattress is disclosed which comprises an inflatable and deflatable flexible body enclosing an air chamber having a resilient means urging the opposite upper and lower walls of the body apart while being yieldable to permit the body to be folded and deflated.
In a final example, an air pump is disclosed which includes a number of inflatable chambers which form a closed container for defining a pumping chamber. The container is fitted with one-way inlet and outlet valves to effectuate the pumping operation. In one embodiment, the container is cylindrical with seven to nine longitudinal air chambers forming the walls of the chamber. The ends of the cylindrical container are fitted with the inlet and outlet valves.
Thus, there is a need in the art for an internal air pump for inflatable devices which exhibits a thin-walled, highly elastic, lightweight, robust, durable, flexible plastic construction in which the entire air pump is self-adjusting and highly reliable against failure, enables inflation of the inflatable device to specific air pressures, and incorporates a design that maximizes the air volume exhausted from the pump to the inflatable device.